I took my roommate's SIG 228 to a gunsmith to change the hammerspring, but the gunsmith was not at the range I frequent. The gunshop worker said I could leave the gun, but I had to be 21 or else they couldn't give it back. Is this true or not? This does not make any sense; this is basically saying that if I want to refinish my gun or send it in for repair work, I cannot do so because I'm not 21.